Senate Majority Leader Harry Reid (D-Nev.) abruptly reversed plans to compromise over Iraq legislation with Republicans after a meeting in New York where antiwar leaders pressured him to be more aggressive in ending the war.

The meeting on Monday, which was not publicly announced, showed the acute pressure that Democrats face as they try to convince this increasingly restive group that Democrats are doing everything they can to pull U.S. troops out of Iraq more quickly than President Bush wants.

Less than a day after Reid met with several leaders of the antiwar movement in New York, he and other Democratic leaders took a hard line against wooing wavering Republicans to their anti-war cause. “We haven’t found much movement with the Republicans. They seem to be sticking with the president,” Reid said Tuesday.

Reid’s session in New York came as he and other congressional leaders were trying to maneuver between two conflicting political goals: Enlisting enough support from Republican lawmakers to force the Bush administration to change its strategy, without compromising so much that anti-war activists will complain of a sell-out.

At the meeting, Reid reportedly tried to explain his limitations and pleaded with anti-war leaders to keep their energies focused on Republicans, not Democrats.

The Reid mission reflected the paradox bedeviling the anti-war movement. It is powerful enough to command constant care-and-feeding by the Democratic Party’s presidential candidates and congressional leaders. But so far it has proven largely impotent in forcing policy changes. But Democrats are now starting to do more than just patronize the movement, as Reid indicated Tuesday.

If Reid stands firm to his Tuesday pledge, he may begin to satisfy an increasingly impatient anti-war movement. Five years after the congressional vote authorizing Bush's march to war, opponents still have had only mixed success in mobilizing a mass protest movement.

Impatience rising, some activists are urging that Democrats who are not aggressive enough in confronting Bush on Iraq themselves be challenged with primary opponents or third-party candidacies in 2008.

“People are feeling like we invested all this time and money in changing the political equation and where has it led us?” said former congressman Tom Andrews, leader of Win Without War, a member of the anti-war coalition Americans Against Escalation in Iraq (AAEI).

Polls show majorities agree with anti-war leaders that the war was a mistake and that troops should come home soon.

But unlike during the Vietnam era, when the size and strength of street protests gradually grew over time, the Iraq war initially produced massive demonstrations that have since petered out. On Saturday, only about 20,000 gathered for what was billed a major peace march.

Despite millions spent and a season of action dubbed “Iraq Summer,” September arrived without the dam breaking Bush’s Republican support for a continued indefinite presence in Iraq.

That’s not how it was supposed to go.

Last April, an energized Tom Matzzie, head of AAEI, visited the offices of Politico to lay out the summer strategy — and the 2008 elections were central to his thinking.

Democrats and the anti-war movement had the GOP “by the balls,” Matzzie argued then, because the party’s conservative base still heavily supported the war, while the rest of the country opposed it.

Republicans would therefore be forced to choose between the president and their base, and the general electorate. If the GOP prevented anti-war legislation from passing this term, he said, a colorful fate awaited it.

“We’re going to smash their heads against their base and flush them down the toilet,” Matzzie said in April. Five months later, the GOP is still unified behind the war.

In interviews in recent days, anti-war leaders laid out the strategy going forward and defended their tactics while the GOP piled on criticism. Republicans contend, in fact, that the war is not front and center with constituents.

One Republican leadership aide, who asked not to be identified, reported that returning members of Congress heard over the summer recess that “illegal immigration, not Iraq” was the top issue of public concern.

But leaders of the anti-war movement aren’t buying it. “Pure spin. Ask Jim Walsh,” Matzzie responded, referring to the House Republican from New York who recently switched his position on the war after being targeted by AAEI.

Matzzie’s rebuttal is typical of a defense that movement leaders make against charges of ineffectiveness. Namely, they deny it by pointing to skeptical public comments made by a growing list of Republican senators and House members under pressure on the war.

Yet lawmakers are only defecting in trickles — which leads to the second defense from anti-war Democrats: Bush’s plugging the dam now will only make the 2008 electoral flood worse.

“Are Republicans really crazy enough to dispute that Iraq is the top issue in the country?” asked Reid spokesman Jim Manley. “If so, that is downright delusional, trending towards fantasyland. If they want to take solace from the fact that they are united as they head off the cliff into certain political oblivion, that is their choice.”

Eli Pariser, the head of MoveOn.org, believes that Matzzie’s spring promise still looks accurate. “I think there’ll be dramatic political consequences for Republicans who continue to back unending war in Iraq. I think President Bush put them in a bind,” he said. “Either Republicans will break with the president or they’ll get fired at the ballot box.”

Increasing the Democratic majority, however, has not been the movement’s first goal, he claimed. “I’d much rather have more Republicans in the Senate and an end to the war than less of them in 2009 and still be [in Iraq],” he said.

The third defense is that the movement is doing all it can — but Bush is simply immovable. Pariser said his group was influential in helping Democrats take control of Congress and in getting a “majority of both congressional bodies on record supporting a timetable for exit,” yet the president responded by expanding the war.

“For any other president, that would have been enough to signal that the public is against the war,” he said. Americans appear similarly skeptical about the president: 77 percent said in a CBS/New York Times poll that Bush would continue his own strategy regardless of whatever Army Gen. David Petraeus recommended, and 66 percent said the same in an ABC/Washington Post poll.

The same polls find that large majorities support a timeline for withdrawal — and a CBS News poll taken after Petraeus’ testimony found the mood largely unchanged.

That dynamic makes Matzzie’s threat a serious one for candidates on the other side of public opinion.

An August survey done for MoveOn by the Greenberg Quinlan Rosner Research firm conducted in seven states with vulnerable GOP senators — New Mexico, New Hampshire, Kentucky, Maine, Virginia, Minnesota and North Carolina — found that voters in those states were inclined, by a 47 percent to 37 percent margin, not to reelect the Republican incumbent, while naming Iraq as the biggest issue.

Greenberg’s group also checked in on House seats for Democracy Corps, polling in 35 Republican House districts and 35 Democratic districts where the incumbent was deemed vulnerable.

He found similar results: Democrats were ahead 52 percent to 41 percent across the board and leading in districts they had just picked up by 55 percent to 37 percent. Marginal Republicans were behind 44 percent to 49 percent.

“The Democrats had very large leads, including in the seats they newly picked up in 2006. The Republicans in the 35 seats we looked at were behind — and this was a named ballot, not a generic ballot,” Greenberg said. “Republicans holding those seats are gravely at risk.”

Yet for frustrated activists, 2009 is far too long to wait. “First things first: Let’s end this war,” said Andrews, of Win Without War.

Andrews, anti-war activist Tom Hayden, Code Pink’s Dana Balicki, and Leslie Cagan, director of United for Peace and Justice, a coalition of anti-war groups, said there is open talk of third-party challenges from the left.

MoveOn recently asked its members whether it should challenge pro-war Democrats in primaries. The results of the query have yet to be released, but the fact that the option is under consideration indicates the profound frustration being felt.

Though patience is running out among activists, said several movement leaders, there is befuddlement as to how to proceed. “If any of us knew which tactic it would be that will end the war, I’d tell everyone to get behind it,” said Cagan.

“I’d be foolhardy to say we have the answer to how to end this war. The good news here is that we’re still growing. The bad news is that the war is still going and we’re not strong enough to end it.”

If the anti-war movement does take on Democrats, it claims it will have the troops needed. Beltway media, said Pariser, don’t notice the spread-out strength of the movement. “I think [the media] still doesn’t really understand what it means to have the kind of targeted and nationally oriented anti-war movement,” he said.

“Since January, our members have done upwards of 7,000 events that got local earned media. I think that’s less visible in Washington, but it’s more powerful.”